Method of working the inner surface of a hollow body



June 3, 1952 J. J. STRMPEN METHOD OF WORKING THE INNER SURFACE OF A HOLLOW BODY 6 Sheets-Sheet 1 Filed Dec. 5, 1948 J- J. STAMPEN June 3, 1952 METHOD OF WORKING THE INNER SURFACE OF A HOLLOW BODY Filed Dec. 5, 1948 's Sheets-Sheet 2 W ZZZ June 3, 1952 J. J. STAMPEN 2,599,025

METHOD 0? WORKING THE INNER SURFACE OF A HOLLOW BODY Filed Dec. 5, 1948 6 Sheets-She et 3 K" E N wwws www/k J. J. STAMPEN June 3, 1952 METHOD OF WORKING THE INNER SURFACE OF A HOLLOW BODY Filed Dec. 5, 1948 -6 Sheets-Sheet 4 Jime 3, 1952 J. J. STAMPEN 2,599,025

METHOD OF WORKING THE INNER SURFACE OF A HOLLOW BODY Filed Dec. 5, 1948 a Sheets-Sheet s I lllll June 3, Y STAMPEN METHOD OF WORKING THE INNER SURFACE OF A HOLLOW BODY Filed Dec. 5, 1948 6 Sheets-Sheet 6 I Q Q 1; q l M 8 h m R S Q gm M w I 2 h r 1 Q, 1 3 g Q w I I Q Q 5 Patented June 3, 1952 UNITED STAT as. PATENT o es-res METHQD' or WORKING THE INNER SURFACE OF 'A nonnownornr Jacob J. stampemgfiollywood, Ill., assignor-to- Babson Bros. 00., a corporationof Illinois.

Application December 3, 194 8; SerialNo; 631-38'2" 7- Claims.

This invention relates to an. apparatus: for working: the inner surface of a: hollow body: having a relatively smallopening: intone wall thereof, and. relates particularly to an apparatus for working the. inner surface of the circumferential weld of a. milker pailhaving. a relatively-small usesa pailpwith a. diameter of 1 5 inches, a

maximum. height ofv 7 inches and an opening in. the. top portion: with a diameter in the neighborhood'of: about 7 inches. This openingis' positioned adjacent one edge of the top portion. While the pail is being used, this opening; is closed by a. lid sealed vacuumtig-htto the pail with. the; lid having connector. nipples for the milker infiations and: also I carrying the pulsator and its. connections. The general 1' construction and; operation: of a; milker of this: typeare' well known and need: not bedescribed further.

' Milker pails of the: above typethat .have: heretofore; been made have involved the use of an overlapped seam or: a butt-welded juncture: be.-

tween. upper". and lower sections of: the pail; which.- extends circumferentially around the finished pail: and: divides the pail into two: approximately equal halves-,a butt-welded juncture being preferred" so as; to avoid internal; pockets-that are difficult and often impossible to clean. In manu facturing the milker" pail there is normally formed an upper part ma'dein one draw or series of draws, in-at least one forming operation, and

a lower. part separately drawn orformed.

. After the butt weldjoining the upper and lowerparts had-been. formed it was found difficult to smooth the inner surface-of. the weld because of: the small. opening; into the pail and because this: opening' istoft center. and adjacent to one ential weld so that it can be smoothed downand:

given all-the advantageouscharacteristics of a truly seamless pail even from theinner surface thereof. A pail finishedwiththe apparatus of this invention has-a completely smooth inner wall whichnot only has: the: desirable. sm'ooth 2. appearance, but which completely avoids. unwashablepocketsbeing formed on thevinner sur face; of the weld; Grinding: andzpolishing; of the: outer suriace is, of=:course, easily accomplished by' conventional machinery.

Other features and advantages of. myv inven-- tion will be apparent from the following? specifi cation,.and the drawings; in which:

Fig. 1 is: a fragmentary :side'. elevation xpartially in section, of oneembodiment of the'ap paratus usectfor roughgrinding theinnei" surface of. the circumferential weld: of: a: milken pail;= said milker pail being. shown in dotted: lines;-

Fig. 2 is a fragmentary end elevationof the-- apparatus of Fig. 1. taken. from the-Frightha-nd side thereof.

Fig. 3 is a. transversesection takemthrougnthe apparatus substantially a1ong:line-3=-3-.of Fig 4,. with the milker pail being. shownv in =-solid lines; Fig. 4: a transverse: sectiomtakeni substan-- tially alongiline14==-4 of-Fig; .2, witlrtlre milk'er pail being. shownin'solid line's.

Fig. 5- is a section taken substantially along; line 5--5- ofFig; 1.

Fig. 6 is: a-iragmentary side elevation of one:

embodiment of the apparatus used/ in polishing. the internal. surfaceoi the; pail weld after the grinding: operation; said pail beingshownhin dotted lines.

Fig. '7 isasectiom taken along; 1ine+l:-: l of Fig.:6:and1- partially broken: away'for clar-ity'of illustration, with: the? milker. pail-being. showm im solid: lines;

Fig. 8: is? a seotion ta-ken substantially; along.

. line18 -8 of Fig. 7.

Fig; 9 is: a section taken substantially along;

ed thereto and'mean'swmounted on the *shaft for operation against the inner surface of: the. nail in the: region of: the circumferential weld upon- The operating; means is rotation- 0f theshaft; dimensioned so that the openingin the pailcan be slipped thereover with the :operating meansbeing withinthe-pail-during-the operation there-- of. Although theapparatus' isprimarily intend:- ed for treating the inner surface of .a=-mi1kerpai1:

adjacent: the circumferential: weld, .it is: believed obviousthatit; can be employedifor treating; the surface of any-hollowi'body; particularlyione haw/ ing-a :relatively. small op'ening-.-in one'- wall thereof, and especially any hollow body having 1' suchwan' opening; in one wall-adjacent one: edge of.v the body and offset from the transverse axis of the body.

In working the inner surface of a hollow body such as a milker pail two operations are preferably used. In one operation the rough weld is ground with an abrasive, while in the second operation this ground weld is polished to provide a smooth continuous surface on the inside of the body or milker pail adjacent the weld. General features of both forms of apparatus are the same, however, as in both forms there is preferably provided a rotatable driving shaft, a rotatable driven shaft spaced therefrom, driving means interconnecting these shafts and means mounted on the driven shaft and including a working member for operation against the inner surface of the body or pail upon rotation of the shafts. The driven shaft, interconnecting driving means and operating means are dimensioned so that the opening in the hollow body can be slipped thereover with the driven shaft and operating means being within the body and the driving shaft extending through the opening. When the body acted upon is the milker pail having a substantially circular circumference, the driven shaft is located at substantially the transverse axis of the pail.

In the accompanying drawings, Figs. 1 to 5 illustrate one embodiment of the apparatus used in the first operation in which the rough weld is ground down. Figs. 6 to 9 illustrate one embodiment of the apparatus in which the ground weld is polished so as to present a smooth appearance.

In the grinding apparatus of Figs. 1 to 5, there is provided a base member I!) upon which the apparatus is mounted. Extending upwardly from this base member is a bearing support havin mounted on the upper end thereof an extended bearing l2 through which extends a rotatable driving shaft l3. The outer end of this driving shaft has attached thereto a driving means, here,

ing means or rigid housing It. Located within this housing is a first circular gear mounted on the end of the driving shaft I3 for rotation therewith, a second circular gear l8 meshing with the first gear I! and mounted for rotation on a'short shaft I9 wholly within the housing I6 and a third circular gear meshing with the second gear l8 and located adjacent the upper end of the housing l6. This third circular gear 20 is fixedly mounted on a driven shaft 2| positioned in the upper end of the housing It and extending therefrom. With this arrange ment the driven shaft 2| is rotated by rotation of the driving shaft I3. In order to aid in assembling the various gears within the housing Hi, this housing is preferably made in two parts with the gears located therebctween and with these parts fastened together by rods, pins, bolts or the like 22.

Attached to the outer end of the driven shaft 2| for rotation therewith are means for operating against the inner surface of the milker on rotation of shafts l3 and 2|. In the embodiment shown in'Figs. 1 to 5 this operating means includes a pair of substantially parallel arms 23 These belts mounted substantially centrally on an annular member 24 that is attached to the driven shaft 2|. Each arm 23 is held in place by means of a pin 25 extending from the annular member 24 through an arm 23.

On each end of the pair of arms 23 there is provided a holder 26 forming a socket that is closed at the sides and the inner end but open at the outer end. Each holder 26 is adapted to hold working member, here shown as a grinding member 21 with this grinding member being fitted loosely in the holder and extending therebeyond. The sides 26a of the holder 26 are attached at the inner end thereof to a block 28 with this block forming the inner end of the holder and being attached to a bar 29. The holder 26 is slidably held between the arms 23 and the ends of the bar 29 are attached to ends of coil springs 30. The other end of each spring 30 is attached to an arm 23 near the outer extremity thereof. With this arrangement each bar 29 and thus the holder 26 are urged outwardly by the tension of the coil springs 30 so that the grinding members 21 are urged against the inner surface of the milker pail 3| in the areas adjacent the circumferential weld 3|a. As can be seen, particularly in Figs. 3 and 4, the arms 23 have lengths substantially less than the diameter of the pail 3| and the outer ends of the holders 25 are normally spaced inwardly substantial distances from the inner surface of the pail.

In the preferred method of making the weld 3 la, the contacting edges of the metal are heated and pressure is applied to fuse the softened metal together. Thus no added welding metal is applied. In the drawings the weld 3 Id is indicated as a line for purposes of illustration only as in the finished construction there is no observableseam.

In order to hold the pail 3| in position, there are provided means embracing the pail around the periphery thereof in the region opposite the path of travel of the grinding members and adjacent the weld 3|a. In the embodiment shown this embracing means comprises a pair of substantially semi-circular metal bars 32 and 33. Each bar is relatively heavy and when in closed position have their ends substantially abutting each other on a diameter of the milker pail 3|. The lower metal bar 32 is preferably made solid while the upper metal bar 33 is preferably provided with a series of openings 33a extending transversely therethrough. As the bars 32 and 33 are preferably made of steel, they serve to conduct heat away from the pail 3|. This heat which is developed by the friction of the grinding members 21 against the inner surface of the pail is often considerable and the provision of means for conducting this heat away from the pail is an important feature of this invention as it avoids possible damage to the metal of the pail caused by overheating thereof in the region of the weld 3|a. The openings 33a in the upper metal bar 33 aid in dissipating the heat in this part 'to the surrounding area. I

' The metal bars 32 and 33 are hingedly attached together at one of their adjacent ends by means of a pair of metal hinge straps 34. These hinge straps are located on opposite sides of the bars 32 and 33 and are attached to the bars by means of pins 35. The opposite ends of the bars 32 and 33 are removably held together by means of a latch 35rotatably mounted on the lower bar 32 and engaging studs 31 on'the upper bar raise the-up erbara'ii from the pail 3| andlower the b'ar on to the pail. When thefupper bar 33 is i'n ripen-position, as shown-by dotted lines in Fig- '2;- it res'ts against a bracket '40 attached to the lower'metal' bar 32 adjacent the hinge straps 34.

In orderto locate properly the mi-l-ker pail- 31 with relationship 'tothe grinding m'em-bers 31, there' is provided means bearing against the pail on the-side opposite the opening 31b. lnthe-embodiment shown in Figs. 1 to 5, this means 'com-,.

prises a locating member 41 in the form of an annular metal plate having the lower portion a "extending downwardly and to the left, as viewed in Fig. 2. Thebottomend "of 'thislower portion M a :has attached thereto a collar Mb rbtatably zmounted ona shaft 42, which is-attached to the base member HI. This collar 41:!) Is -held between amounting member 43 in which the-shaft 42' is held and an annular collar '44 fixedlymounted adjacent the outer'endof the-v shaft 42. The moun'tingmeniber 43 and annular collar 4 permit movement of the locating imemb'er 4| in a plane which is substantially :parallel to theu'pp'er and lower metal bar-s32 and '33. In

order to operate thelocating member 4i, there is,-

provided an outwardly extending :handle' 45 atta'ohed'to'the locating member adjacent the top thereof.

Although the apparatus of Figs. 1 to 5 'is' primarily'intended for .grinding downthe inner sure face of the weld, it is believed obvious that with minor modifications this same 'apparatus'could be used for anyworking operation such as the final polishing operation. The'prin'cipal changes would, of course, 'beto provide apolishing mema;

her in .place of thegr-inding member 2?. In

actuaripractice, however, order to increase production, it "is preferred that a separate mechanism'be employed for the polishing operation.

The *polishing' apparatus is constructed gener-f ally similar to the apparatus :used'for-grinding. 'Ihef principal difference between the grinding apparatus 'and polishing apparatus is that in the polishing apparatus, as illustrated, only one polishing member is employed'and -'a different.

type of embracing means-is used for holding the milkerpail inpla'ce during the polishingoperatlon. 'In the polishingapparatus there is no need 'toprovi'dethe' heat conducting bars as "the .heat

generated during theipolishing operation is much less than that generated during thegrindirig operation. :Also means are provided the polishing apparatus for reciprocating the imilker pail laterally'of the planexof rotationof theop'e'rating means which does 'the polishing during the rotation "thereof. This reciprocating -means -is--emplayed so-that =the polished areawill blend smoothly into the interior surface :on either side of the polished area. 7

- 1mm; fdr'awmgsyFigst .6 stor-9 illustrate one em- 6 bodiment of the polishing -apparatus in this embodiment-there is provided a ba'semembr 43, a" bearing support :41 at "one end thereof; an 'extended b'earing fl held by-the bearing support l1 and a drivingishaft 4'9 within the extended bearing 48. The outer end-0f the driving-shaft hasattached thereto' a belt pulley '50 which =is driven by'a pair of driving belts '5 l. These-belts may :be driven by an electric motor .or --:other source ofpow er.

n ne inner end-of theext'ended bearing that is opposite-ithe" pulley has attached theretoa mountingmeanathere shown as a irigid'lho'using 52. I he drivingshaft 49 extends into the rigid housing-52 and has: mounted on the end thereof adr iving means; here shown as a first circular gear ikmountednonthe end 'ofthefshaft -49, andaa seoond (iildul alf-Qgear'fil i'in --engagement with the first 'ge'ar. The s'ec'ond' gear 54 is mounted ozra driven shaft 5'5 so that rotation of the igears causes rotationof thedriven shaft. This driven shaft 55 extends :beyond the housing 52 on-the side opposite the driving :shaft 49. The outer end of the driven "shaft'ih'as attached thereto an operating imeans, here shown as including an arm 56, mounted for rotation with the driven shaft 355 and carrying :-on the end thereof a working member, here shown as a "polishing member-51.

Theipolls'hing member 5 is mounted :on ap'air of substantially parallel :rods :53 which are slidablyheld in the outer end fof the arm 56. Each rod 158 is'z held-tin a longitudinal substantially circular cavity 56a opening :at :the' end of "the arm 56. located ineach'icavity Star-is a compression springillhop'erating" against the inner end OfiitS rodsi58to urge the .polishing member 5 outwardly against the inner surface of the milker pail 30 Sin-"the area adjacent the weld 31 a. Adjacent the inner end of each :rod "58 there :is vlocated -.'a set screw 60 :movable in a longitudinal slot 561) in the arm :56. With these set screws 60 the pressure "of the polishing .m'ember against the milkerlmay bereg-ul'ated ;to :either amaximum or minimum 'value. When the set screws Y fifl z'are loosened so that they do not engage the sides of the slots 5612, the vforce developed will zbeathe centrifugal force of the polishing member 157! and associated structure.

Inorder to balance the arm 56, there is pro-- vided a counterweight 561: "formed as a part of thearm. This counterweight extends beyond the driven shaft 55'on the end of the arm opposite the polishing'imeniber 5 ln orderjto -h'old the milker pail '31 in position during the polishing operation there "isprovided an embracing means for the pail. This embracingmeans "serves .as a locating means for the pail and engages the milker'pail around theperiphery thereof "in the 'regiono'pposite-the path of Y travel ofthe p'olishing memberand also-on the side-of thepail oppositethe" opening 341). In the embodiment shown, this "embracing or locating means comprises a pair of grasping members 6| and 62 -"I he' se grasping members-which maybe constructed "of bloeks of Wood'have hollowed-out sections-"61 a and 62 a each substantially semicircular in contour so that they will grasp and hold the outercircumferentialsurface of the pail when the 'members S-I and Ill are arranged to-- gether; as s'hown in'Fig. 7. Both grasping members lil and '62 are -ofsusbtanti allyrectangular shape-and the =:upper member 62 is h'inge'dl-y mouutedaat one edge" thereof on a-=correspondmg edge br the tower enema-m b'y the hinge structure 63. Because of the hinge 63;

the milker pail 3| is positioned so that the open-,

ing 3|b is on the bottom thereof during the polishing operation, it has been found necessary to turn the pail so that oil will be less likely to spill out during the polishing operation. In the embodiment of the invention shown in the drawings, this is accomplished by arranging the bottom of the lower grasping member 6| at an acute angle to the horizontal, as shown in Fig. 4. In this arrangement the driving shaft 49 and the bearing 48 are located adjacent the top of the pail opening 3|a and a line connecting the driving shaft 49 and the driven shaft 55, and at a right angle to at least the driven shaft, is at an acute angle to the horizontal.

The lower grasping member 6| has attached thereto a pair of extended collars 35 in the form of circular pipes. Each collar 95 is at a lower corner of the lower grasping member 6| and are arranged substantially parallel to each other and at right angles to the plane of the grasping member. Each collar is supported on a substantially circular bar 69 with these bars being arranged substantially parallel to each other These bars 63 have their ends attached to mounting members 51 which are supported on the base member 46. As can be seen from Figs. 6 and 7, the rear bar 66 is at a higher level than thefront bar.

The provision of the collars 35 and circular bars 86 permits reciprocation of the grasping member GI and 62 and thus the milker pail 3| during the polishing operation. Such reciprocation results in a blending of the polished area with the surfaces on either side thereof so as to give a smooth appearance to the inner surface:

of the milker pail.

In the embodiment shown, the reciprocation of the milker pail is obtained by providing a metal strap 83 rotatably attached to the bottom surface of the lower grasping member 6| with this strap being rotatably fastened to the end of a lever 69, which is mounted for rotation about a fulcrum 69a. The lever 69 is provided with a handle portion 69b so that the lever may be moved back and forth and thus reciprocate the grasping member and the pail during the polishing operation.

The polishing member 51 may have any form desired. In the embodiment shown, the member comprises a trough-like holder 5111 having a felt body 51b extending therefrom with this felt body being surrounded with a cloth layer 510. The actual polishing'element that is used is a strip of emery cloth 57d on the outermost surface of. the cloth layer 510. Means are preferably provided for removing the emery cloth whenever it becomes worn and replacing it with a new one.

In the working or finishing of the weld 3 I a, the weld is first. ground down by means of the apparatus shown in Figs. 1 to 5 and then polished in the apparatus shown in Figs. 6 to 9. In the operation of the apparatus of Figs. 1 to 5 the upper metal bar 33 is turned to its open position, as illustrated in dotted lines in Figs. 5 and 6, and

the milker pail is then slipped over the holders 26, arms 23 and gear housing 5 and moved to the position shown in Fig. 4. The grindingmembers 21 may thenbe placed within their holders 26 by moving the holders inwardly against the action of the springs 30 until there is room for inserting the grinding members within the holders. The locating member 4| is then rotated into position as shown in Fig. 1, and the bottom of the milker pail pressed against this member.'

The upper metal bar 33 is then moved into position by means of the handle 39 and the upper and lower members 32 and 33 locked together by means of the latch 36. Power is applied through the pulley M to rotate the driving shaft l3 and thus the driven shaft 2|. The arms 23 are rotated at the desired rate of speed and the grinding members 41 are forced against the weld 3| by a combination of spring and centrifugal forces acting on these grinding members.

erated in the area of the pail adjacent the weld 3|a is conducted away from the pail by the metal bars 32 and 33. After the weld has been ground down the desired distance, the rotation of the apparatus is stopped, the upper metal bar released by opening the latch 36 and this bar turned around its hinge to the position shown in the dotted lines in Fig. 2. The milker pail is then removed from the apparatus.

In the polishing operation the upper grasping member 62 is turned to the position shown in the dotted lines in Fig. '1 andthe opening 3|b in the milker pail is slipped over the polishing member 51, arm 59 and gear housing 52. The

1 milker pail is positioned within the lower grasping member 6| so that the side of the pail rests against the hollowed out section Ela and the bottom of the pail is pressed against the rear of this hollowed out section. The upper grasping member 62 is then rotated about its hinge 63 to the position shown in Fig. 7 and the lock 64 is closed. Power is applied to the apparatus through the belt pulley so as to cause rotation of the driving shaft 49 and the driven shaft 55. This causes rotation of the arm 56 and thus applies a polishing action to the inner surface of the pail adjacent the weld 3|a. In order to aid in the polishing operation it is preferred that a polishing oil be introduced into the interior of the pair before the power is turned on.

During the polishing operation the polishing member 51 is forced outwardly against the pail by a combination of centrifugal force and the force of the springs 59. During the polishing operation the lever 69 is reciprocated back and forth around its fulcrum 59a thereby causing the extended collars 65 to slide on the rods 66 and set up reciprocation of the milker pail. Such recip rocation causes the polished area to blend smoothly with the remainder of the pail. After the weld has received a sufficient polishing action, the power is shut off and the upper grasping member 62 is unlatched from the lower grasping member 6|. The upper grasping member is then moved to open position and the milker pail re-- Heat gen- .entia-l surface; of; a milker-pail; having; a; substantially circular side; wall; containing-a substantially circular butt-welded seam,; and having; a small opening'of, a diameter less, than one-half the diameter of the pailin the; top wallI of the pail and offset from the center thereof, comprising: positioning the pail on an elbow-shaped working tool that'comprisesa rotatable driven shaft within the pail arranged at, substantially right angles to. the; plane of. the seam and substantially concentric to the seam, driving means operatively connected thereto and; including a portion extending through said opening in the pail and to the driven shaft, and collapsible working means mounted on the driven shaft for rotation therewith, and normally bearing against said inner surface for operation-thereagainst during rotation of the driven shaft, the collapsible working means, and thedriven shaft andv adiacent driving means having diameters, widths and lengths, such that when, the working means is in a collapsed state the pail may be; readily slipped thereover;; clamping the-pail in said position; and rotating thev driven shaft and associated working means with the working means in contact with the inner surface of the pail at the seam.

2. Themethod of grinding the inner circumferential. surface of a milker pail having a substantially circular side wall containing a substantially circular butt-welded seam and having a small opening of a diameter less than one-half the diameter of the pail in the top wall of the pail and offset from the center thereof, comprising: positioning the pail on an elbow-shaped I grinding tool that comprises a rotatable driven shaft within the pail arranged at substantially right angles to the plane of the seam and substantially concentric to the seam, driving means operatively connected thereto and including a portion extending through said opening in the pail and to the driven shaft, and collapsible grinding means mounted on the driven shaft for rotation therewith and normally bearing against said inner surface for operation thereagainst during rotation of the driven shaft, the collapsible grinding means and the driven shaft and adjacent driving means having diameters, widths and lengths such that when the grinding means is in a collapsed state the pail may be readily slipped thereover; clamping the pail in said position with apparatus including heat-conducting and heat-dissipating means bearing against the outer circumferential surface of the pail in the region of the seam; and rotating the driven shaft and associated grinding means with the grinding means in contact with the inner surface of the pail at the seam.

3. The method of polishing the inner circumferential surface of a milker pail having a substantially circular side wall containing a substantially circular butt-welded seam and having a small opening of a diameter less than one-half the diameter of the pail in the top wall of the pail and offset from the center thereof, comprising: positioning the pail on an elbow-shaped polishing tool that comprises a rotatable driven shaft within th pail arranged at substantially right angles to the plane of the seam and substantially concentric to the seam, driving means operatively connected thereto and including a portion extending through said Opening in the pail and to the driven shaft, and collapsible polishing means mounted on the driven shaft for rotation therewith and normally bearing against said inner surface q pe at on; thereagainst duri g. rota? tion of the driven shaft, the collapsible polishtng means and the driven shaft and adjacent driving means having diameters, widths and lengthssuch that, when the polishing means is in a collapsed state the pail may be readily slipped thereover;

, clam-ping the pail insaid position; and rotating the driven shaft and associated polishing means while reciprocating the pail laterally of the plane of rotationofthe, polishing means with the polishing means in; contact with the inner surfacerof the pail at the seam.

i. The method of working; the inner circum; feren-tial surface of a. milker pail, having asub stantially circular side wall containing a-substan tiall-y circular butt-welded seam and having a small opening of a diameter less thanone-half the diameter; of the pail inthe top Wall of; the pail and offset from the center thereof, comp is ing: positioning the pail 'on an elbow-s ped working tool that, comprises a rotatable; dri en shaft within the pail arranged at substantia ly right angles to the plane of the seam and; s b stantially concentric to the seam, a rotatable driving shaft substantially parallel tov th driven shaftand extending through said pail opening into the pail, mounting means within the pail extending from the driving shaft to the driven shaft and upon which the driven shaft is rotateably mounted, driving I means carried by said mounting means and interconnecting thedriving and driven shafts, and collapsible workingmeans v mounted on the driven shaft for rotation there-v with and normally bearing against said inner surface'for operation thereagainst during rota-r tion of the driven shaft, the collapsible wor g means, driven shaft, inner endof the; driving shaft, mounting means, driving means, work 3 means, and associated parts havingdiameters, widths'andlengths such that when the working means is in acollapsed state thepail may be readily slipped thereover; clamping thepail in said position; and rotating the driving shaftand, thus the driving means, driven shaft and associated working means with the working means in contact with the inner surface of the pailatrthe,

seam,

5. The method of grinding the inner cireumrferential surface of a mil-ker pail having a-sub-, stantially circular side wall containing a substan--. tially circular butt-Welded seam and having a small opening of a diameter less than one-half the diameter of the pail in the top wall of the pail and offset from the center thereof, comprising: positioning the pail on an elbow-shaped grinding tool that comprises a rotatable driven shaft within the pail arranged at substantially right angles to the plane of the seam and substantially concentric to the seam, a rotatable driving shaft substantially parallel to the driven shaft and extending through said pail opening into the pail, mounting means within the pail extending from the driving shaft to the driven shaft and upon which th driven shaft is rotatably mounted, driving means carried by said mounting means and interconnecting the driving and driven shafts, and collapsible grinding means mounted on the driven shaft for rotation therewith and normally bearing against said inner surface for operation thereagainst during rotation of the driven shaft, the collapsible grinding means, driven shaft, inner end of the driving shaft, mounting means, driving means, grinding means, and associated parts having diameters, widths and lengths such that when the grinding means o if ism a collapsed state the pail maybe readily slipped thereover; clamping the pail in said position with apparatus including heat-conducting and heat-dissipating meansbearing against the outer circumferential surface of the pail in the region of the seam; and rotating the driven shaft and associated grinding means with the grinding means in contact with the inner surface of the pailat the seam.

' 6. The method of polishing the inner circumferential surface of a milker pail having a substantially circular side wall containing a substantially circular butt-welded seam and having a small opening of a diameter less than one-half the diameter of the pail in the top wall of the pail and offset from the center thereof, comprising: positioning the pail on an elbow-shaped polishing tool that comprises a rotatable driven shaftwithin the pail arranged at substantially rightwangles to the plane of the seam and substantially concentric to the seam, a rotatable driving shaft substantially parallel to the driven shaft and extending through said pail opening into the pail, mounting means within the pail extending from the driving shaft to the driven shaft and upon which the driven shaft is rotatably mounted, driving, means carried by said mounting means and interconnecting the driving and driven shafts, and collapsible polishing means mounted on the driven shaft for rotation therewith, and normally bearing against said innersurface for operation thereagainst during rotation, of the driven shaft, the collapsible polishing means, driven shaft, inner end of the driving shaft, mounting means, driving means, polishing means, and associated parts having diameters, widths and lengths such that when the polishing means is in a collapsed state the pail maybe readily slipped thereover; clamping the pail in said position; and rotating the driving shaft and thus the driving means, driven shaft and associated, polishing means While reciprocating the pail laterally of the plane of rotation of the polishing means with the polishing means inpcontact with the inner surface of the pail at the seam.

7. The method of working the imier circumferential surface of a milker pail having a substantially circularside wall containing a substantially circular butt-welded seam and having asmall opening of a diameter less than one-half 12 the diameter of the pail in the top wall of the pail and offset from the center thereof, comprising: positioning the pail on an elbow-shaped working tool that comprises a rotatable driven shaft within the pail arranged at substantially right angles to the plane of the seam and substantially concentric to the seam, a rotatable driving shaft substantially parallel to the driven shaft and extending through said pail opening into the pail, first mounting means within the pail extending from the driving shaft to the driven shaft and upon which the driven shaft is rotatably mounted as its sole support, driving means carried by said mounting means and interconnecting the driving and driven shafts, a relatively narrow second mounting means arranged closely adjacent to the driving shaft and serving as a support therefor and rigidly connected to the first mounting means, and collapsible working means mounted on the driven shaft for rotation therewith and normally bearing against said inner surface for operation thereagainst during rotation of thedriven shaft, the collapsible working means, driven shaft, inner end of the driving shaft, mounting means, driving means, working means, and associated parts having diameters, widths and lengths such that when the working means is in a collapsed state the pail may be readily slipped thereover; clamping the pail in said position; and rotating the driving shaft and thus the driving means, driven shaft and associated working means with the Working means in contact with the inner surface of the pail at the seam.

JACOB J. STAMPEN.

REFERENCES CITED The following references are of record in the file of this patent:

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